JPH036746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a speed control device that automatically adjusts dynamic characteristics in a DC motor control system, that is, an automatic tuning speed control device.

Generally, in this type of control device, the proportional gain of the speed regulator is adjusted each time according to the amount of ^GD2 (amount equivalent to the moment of inertia), the amount of magnetic field, etc., which changes depending on the type of motor or load fluctuation. It is desirable to automatically adjust the settings online without having to do so.

[Prior art and its problems]

As a device of this kind, the applicant has already proposed a control device as shown in FIG. 1 (see Japanese Patent Application No. 75416/1983). Note that FIG. 1 is a configuration diagram showing a conventional example of such a control device.

In the figure, 1 is a speed regulator (ASR), 2 is a current regulation system including a current regulator (ACR), 3 is a field flux element of a DC motor, 4 is a motor starting time constant element; 4 constitutes a DC motor. Also, 5 is a divider, 6 is a band pass filter, 7, 11 is a multiplier, 8, 9, 1
2 is an integral element, 10 is a proportional element, and 5 to 12 constitute an automatic tuning circuit A.

The operation will be explained.

Speed regulator (ASR) 1 has startup time constant element 4
An adjustment output is output so that the speed actual value (detected value) n obtained through the control is equal to the set (target) value n ^* , and the adjustment output becomes the current command value in the current adjustment system 2. In other words, switch S1 is speed regulator 1
When the switch S1 is on the side, the output of the speed regulator 1 is directly applied to the current regulating system 2, but when the switch S1 is in the state shown, the output of the speed regulator 1 is guided to the adder AD.
Various quantities calculated as follows are added. In the automatic tuning circuit A, the multiplier 11 simulates the magnetic field amount, the integral element 12 simulates the starting time constant, and the estimated speed value n^ obtained via the starting time constant model (integrator) 12 is simulated.
and the actual speed value n obtained through element 4, the deviation e (=n=-n^) is integrated by integral element 9, and the output is fed back to the input side of model 12. . Note that the (^) mark indicates an estimated value. In this way, the output of the field model (multiplier) 11 simulates the motor generated torque τ _n , and the output of the integral element 9 simulates the load disturbance torque τ _{l .} τ^ _n . Further, the automatic tuning circuit A adds a rectangular wave signal δ of a very small constant frequency to the output of the speed regulator 1 in an adder AD in order to calculate the field amount φ and the starting time constant T _n . Switch the output
1 as a current command value to excite the control system and change the speed.On the other hand, only the rectangular wave signal component is extracted from the deviation e through the bandpass filter 6, and the multiplier 7 returns it to the original rectangular signal. The signal is multiplied by the wave signal δ, and the output thereof is further integrated by the integral element 8. In this way, the integral element 8 continues to output until the phase difference ψ between the signal δ and the signal δ' passed through the filter 6 reaches 90°, and at the point when the phase difference reaches 90°, that is, the integral element 8 When the input becomes zero, its output becomes constant, and the loop made up of symbols 6 to 12 is in an equilibrium state. Note that the multiplier 7
The outputs of are expressed as power (DC) components of signals out of phase with each other, such as δδ'cosψ. When the loop is balanced, n = n^ (e = 0), and the output of integral element 9 is the estimated value T _p proportional to τl/T _n
(τl/T _n )^, and the output of the integral element 8 becomes the estimated value T _p (φ/T _n )^ which is proportional to φ/T _n . Here, T _p is a starting time constant of a predetermined value set in the integral element 12 . Therefore, T _p
If the quantity (φ/T _n ) is given as the divisor of the division element 5, the one-cycle transfer function G _p of the control system is G _p =K _p・1+ST _i /ST _i・(l/T _p ( φ/T _n )^・1/1+ST _a・φ/ST _n , the field flux component φ and the starting time constant component
T _n cancel each other out, resulting in a transfer function G _p
is constant regardless of changes in φ and T _n , so the response of the control system is always optimal. Note that Kp1+ST _i /ST _i , 1/1+ST _a , and φ/ST _n represent the transfer functions of the speed regulator, current regulation system, and DC motor, respectively. Furthermore, since the adder AD is given the estimated amount T _p (τl/T _n )^ from the integral element 9, it compensates for the change in the load torque τl before the speed regulator generates the correction signal. In other words, since we are trying to perform feed forward control,
The speed fluctuation due to the change in load torque τl is φ, T _n
This will be suppressed regardless of changes in . In addition, S
Reference numeral 1 designates a switch for switching between using and not using automatic tuning to switch to a simple ASR-ACR control loop and continue operation when automatic tuning is not performed properly.

In other words, this method adds a constant frequency signal δ to the speed regulator output, uses this as a current command value to excite the control system, estimates its parameters (φ, T _n ), and estimates the speed regulator parameters (proportional (gain) is automatically corrected. However, even with this type of system, when operating in a current limited state due to a heavy load or sudden acceleration/deceleration, or when controlling the converter using a control method without circulating current, there are There is a drawback that parameter estimation of the control system becomes unstable during the uncontrolled period.

[Purpose of the invention]

This invention was made in view of these points,
It is an object of the present invention to provide an automatic tuning speed control device that can operate more stably even when operating in a current limited state or in an uncontrolled state during forward and reverse switching.

[Key points of the invention]

The main point is that in a DC electric control system equipped with an automatic tuning circuit, when it becomes impossible to estimate the motor's magnetic flux and starting time constant, such as during current-limited operation or when the power converter is switched in the forward or reverse direction,
The point is that the input of the integrator that performs the estimation is turned off to maintain the estimated value at a constant value, thereby stabilizing the control.

[Embodiments of the invention]

FIG. 2 is a block diagram showing an embodiment of the present invention. As is clear from the figure, this example
In contrast to the conventional circuit shown in FIG.
3. OR gate 14 and switches S2, S3,
The feature is that S4 is added, and the rest is the same as the conventional example.

In other words, the switch S2 does not change the actual speed value due to the δ signal during current-limited operation or when switching the power converter forward or reverse, and the output T _p (φ/T _n )^ of the integral element 8 is estimated. This is provided to prevent the switch S2 from becoming disabled and shifting in an unnecessary direction. In such a case, the input to the integral element 8 is turned off by operating this switch S2, and its output T _p
(φ/T _n ) is maintained at a constant value. The comparator 13 detects the current limit state, operates when the output from the divider 5 is above a predetermined level, and operates the switch S2 via the OR gate 14.

In addition, when the power converter is controlled using a method without circulating current, both the current and speed are uncontrolled while the forward and reverse converters are being switched. By applying this to switches S3 and S4 and operating them,
The inputs of integral elements 9 and 12 are turned off and their outputs T _p (τl/T _n )^ and n^ are held constant to prevent parameters from becoming inestimable and shifting in unnecessary directions. There is. At this time, the signal indicating that the forward/reverse switching is in progress is also applied to the switch S2 via the OR gate 14, so the integral element 8 is also controlled in the same manner as described above.

〔Effect of the invention〕

As described above, according to the present invention, a simulator is provided that estimates at least the motor field flux, starting time constant, and load torque from the actual values (detected values) of the motor speed and current, and these estimated values are used to estimate the motor field flux, starting time constant, and load torque. In a device that automatically corrects the proportional gain of the speed regulator to stabilize the control system, when operating in a current-limited state or when an uncontrolled state occurs due to forward or reverse switching of the converter, The input to the integrator that estimates the motor field flux and starting time constant, or the integrator that estimates the load torque and speed is cut off to hold each estimated value constant, resulting in more stable operation. This provides the advantage of being secured.

Note that the present invention can be widely applied not only to the above-mentioned DC motor, but also to a control device for control objects (including AC motors) having similar transfer characteristics.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional example, and FIG. 2 is a block diagram showing an embodiment of the present invention. Code explanation, 1...Speed regulator (ASR), 2...
Current adjustment system (ACR system), 3... Field element, 4...
Start-up time constant element, 5...Divider, 6...Band pass filter, 7, 11... Multiplier,
8, 9, 12... Integral element, 10... Proportional element,
A...Automatic tuning circuit, S1-S4...Switch, AD...Adder.

Claims (1)

[Claims] 1. A speed regulator which receives the deviation between the actual speed value and the target value of the DC motor and outputs a control output so that the deviation becomes zero, and which converts the output of the speed regulator into a current command value. A speed control device for a DC motor, comprising: a current regulator that adjusts a motor current of the DC motor; and an automatic tuning means that automatically adjusts the proportional gain of the speed regulator according to load fluctuations, the automatic tuning means a first multiplication means 11 which takes in and multiplies the adjustment output of the current regulator and the output of the third integration means 8 described later, thereby simulating the amount of field of the electric motor and outputting an estimated value of the torque generated by the electric motor; , a first integrating means 12 that receives and integrates the output of the first multiplier 11 to simulate a starting time constant of the motor and outputs an estimated value of the motor speed; and an actual speed value of the motor. a second integrating means 9 which receives and integrates the deviation from the estimated value and feeds the output back to the input side of the first integrating means 12 as the estimated value of the load disturbance torque; and a rectangular wave signal δ of a constant frequency. , an adding means for adding the rectangular wave signal δ, the output of the speed regulator, and the output of the second integrating means 9 and providing it to the dividing means 5 described later; and an actual speed value of the electric motor and its estimation. a bandpass filter 6 that takes in the deviation from the value, extracts and outputs the rectangular wave signal, and multiplies the rectangular wave signal δ from the source and the rectangular wave signal δ′ from the bandpass filter 6; The output of the second multiplication means 7 is inputted and integrated, and the phase difference between the two rectangular wave signals becomes 90 degrees, so that the output of the second multiplication means 7 is said third integrating means 8 outputs a constant output when it becomes zero; and the output of said third integrating means 8 is inputted, and the output of said adding means is divided by said third integrating means 8 and input to said current regulator. said dividing means 5, and when a current limit state is detected from the output of said dividing means 5, or when it is detected that forward/reverse conversion switching of a converter constituting a power supply circuit of said electric motor is in progress. At this time, it is detected that the first switch means S2 which cuts off the input of the third integrating means 8 and holds its output constant, and the converter constituting the power supply circuit of the electric motor are being switched for forward/reverse conversion. The second integrating means 9 and the first integrating means 12 are further provided with second switch means S3 and S4 that cut off the respective inputs of the second integrating means 9 and the first integrating means 12 to keep their respective outputs constant. Features: Speed control device for DC motors.